Inactivation of the Sinorhizobium fredii HH103 rhcJ gene abolishes nodulation outer proteins (Nops) secretion and decreases the symbiotic capacity with soybean Authors Maria do C. C. P. de Lyra Department of Microbiology, Faculty of Biology, University of Sevilla, Spain F. Javier López-Baena Department of Microbiology, Faculty of Biology, University of Sevilla, Spain Nuria Madinabeitia Department of Microbiology, Faculty of Biology, University of Sevilla, Spain José María Vinardell Department of Microbiology, Faculty of Biology, University of Sevilla, Spain María del Rosario Espuny Department of Microbiology, Faculty of Biology, University of Sevilla, Spain María Teresa Cubo Department of Microbiology, Faculty of Biology, University of Sevilla, Spain Ramón Andrés Bellogín Department of Microbiology, Faculty of Biology, University of Sevilla, Spain José Enrique Ruiz-Sainz Department of Microbiology, Faculty of Biology, University of Sevilla, Spain Francisco Javier Ollero Department of Microbiology, Faculty of Biology, University of Sevilla, Spain Keywords: Sinorhizobium fredii HH103, gene rhcJ, type III secretion system, nodulation outer proteins (Nops), soybean Abstract It has been postulated that nodulation outer proteins (Nops) avoid effective nodulation of Sinorhizobium fredii USDA257 to nodulate with American soybeans. S. fredii HH103 naturally nodulates with both Asiatic (non-commercial) and American (commercial) soybeans. Inactivation of the S. fredii HH103 gene rhcJ, which belongs to the tts (type III secretion) cluster, abolished Nop secretion and decreased its symbiotic capacity with the two varieties of soybeans. S. fredii strains HH103 and USDA257, that only nodulates with Asian soybeans, showed different SDS-PAGE Nop profiles, indicating that these strains secrete different sets of Nops. In coinoculation experiments, the presence of strain USDA257 provoked a clear reduction of the nodulation ability of strain HH103 with the American soybean cultivar Williams. These results suggest that S. fredii Nops can act as either detrimental or beneficial symbiotic factors in a strain-cultivar-dependent manner. Differences in the flavonoid-mediated expression of rhcJ with respect to nodA were also detected. In addition, one of the Nops secreted by strain HH103 was identified as NopA. [Int Microbiol 2006; 9(2):125-133] Downloads PDF Published 2010-02-25 Issue Vol. 9 No. 2 (2006) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.
